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What happens when a transistor turns off?
When the transistor is turned off, the transistor acts as an insulator, and the LED doesn’t light. R2: This 1 kΩ resistor limits the current flowing into the base of the transistor. You can use Ohm’s law to calculate the current at the base.
What is the basic function of a transistor?
Transistor, semiconductor device for amplifying, controlling, and generating electrical signals. Transistors are the active components of integrated circuits, or “microchips,” which often contain billions of these minuscule devices etched into their shiny surfaces.
What are the two main function of transistor?
A transistor is a kind of solid semiconductor device, which has many functions, such as detecting, rectifying, amplifying, switching, voltage stabilizing, signal modulating and so on. As a variable current switch, the transistor can control the output current based on the input voltage.
What happens when you use a transistor as a switch?
Transistors that are fully “ON” are said to be in their Saturation region. Transistors that are fully “OFF” are said to be in their Cut-off region. When using the transistor as a switch, a small Base current controls a much larger Collector load current.
When does no current flow through a transistor?
If the base-emitter voltage is below 0.7 V, the transistor is in “cutoff” and no current flows through the emitter or through the collector. That’s it. That’s how a BJT works. The collector-emitter current flow is inherent in the construction of the transistor.
What happens at the junction of two anodes in a transistor?
The junction of the two anodes represents the base of a transistor. If you apply a positive voltage greater than 0.7 V to the base, the emitter diode will be forward-biased and current will flow from the base, through the emitter and to ground. The collector diode will be reverse-biased, and no current will flow through that diode.
Why are multiple transistors used in a bipolar transistor?
Sometimes the DC current gain of the bipolar transistor is too low to directly switch the load current or voltage, so multiple switching transistors are used. Here, one small input transistor is used to switch “ON” or “OFF” a much larger current handling output transistor.